Will DNG Output be extended to non-HDR/HDRi output

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Al Darby
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Will DNG Output be extended to non-HDR/HDRi output

Postby Al Darby » Tue May 06, 2014 2:32 pm

Now that SilverFast SE, SE Plus, and Ai Studio can now output HDR and HDRi raw scans to the DNG file format, will that be extended to non-HDR/HDRi output?

I never use the HDR/HDRi format, but would dearly love to have DNG, for my 48-24 colour and 16-8 B&W scans. For me the HDR/HDRi scans produce files that are way too big for my needs.

Thank you.

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LSI_Ketelhohn
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Re: Will DNG Output be extended to non-HDR/HDRi output

Postby LSI_Ketelhohn » Fri May 09, 2014 3:35 pm

Dear customer,

We only offer the DNG format for archive scans because the file format only makes sense there.

The DNG files are meant as a DigitalNeGative and are stored for non-destructive editing with a linear base gamma of 1.0.

The files are not suited for processed images because that would contradict the non-destructive-editing idea.
Also processed files have a gamma of 2.2 while .dng files are expected to have a gamma of 1.0.
Other software would ad the gamma adjustment a second time creating an image with a much too high gamma.

Therefor the DNG is only available for the "raw" HDR/HDRi archive formats.

Kind regards,
Arne Ketelhohn.

Al Darby
SilverFast Beginner
Posts: 18
Joined: Mon Jan 17, 2011 1:44 am
Scanner: Plustek OpticFilm 7600Ai
SilverFast Product: Ai Studio

Re: Will DNG Output be extended to non-HDR/HDRi output

Postby Al Darby » Sat May 10, 2014 1:51 am

That's all very well and good, but your position does not take into consideration the workflow of many of your customers.

I don't use HDR/HDRi at all, nor do I do much, if any, adjustments in SF8 AI. I basically just scan the image to a TIF file.

From there, I convert the TIF to a DNG and delete the TIF, pre-process the DNG in PS LR, then pass the DNG to PS CC for final processing and TIF (or PSD) file creation. The TIF is then "exported" to JPG, in PS LR.

In summary it's 1) scan to TIF, 2) convert TIF to DNG, 3) PS LR processing, 4) DNG to TIF using PS CC and 5) TIF exported to JPG in PS LR.

I end up with 3 versions of the image, as follows:
1. DNG – The original scan, saved as a Digital Negative
2. TIF –The work file used to do the restoration, also for use, if future changes are required
3. JPG – A full sized copy of the scanned / restored image, for viewing, printing or distribution

While this may not conform to a "purist" approach, it's a real world, working for a living approach. I hope some time, in the not too distant future you can see your way clear to extending DNG to non-HDR/HDRi. As for the gamma problems, I would think that any DNG file you created would at least have the correct gamma. By definition any editing done to a DNG file is non-destructive, so that point is specious at best.

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LSI_Ketelhohn
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Re: Will DNG Output be extended to non-HDR/HDRi output

Postby LSI_Ketelhohn » Wed May 14, 2014 9:26 am

Dear customer,

I am afraid that is not the workflow most of our customers use.

The DNG format is a digital negative and treated as such by SilverFast.
It always should use a gamma of 1.0.
Saving other data in the file would violate the non-destructive aspect of the file format.
Using a different gamma is already a change to the image and not the original data which is supposed to be in a DNG.

Currently it is not planned to change this behaviour or support DNG for other outputs.

Kind regards,
Arne ketelhohn.


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